System of color standards



Jan. l

4 927 B. A. AMES E-r A.

SYSTEM 0F COLOR STANDARDS led July 13. 1922 7l.

mes/375: Mawmi .5.

Patented Jan.' 4, i927.

UNITED STATES 1` 1ilvrE1a1f OFFICE.

BLANCHE .AMES AMES,

sYsTEMVoF coLon STANDARDS.

vApplica/mm med my 13,- 1922. serial No. 574,630.

This invention relates t0 a system ofn cards. The present inventionbelongs to the standards for the comparison of color, for last mentionedclass of device, and com rises the purpose of enabling the color of anobject or surface to be determined in terms\ of a known and definitepigmented surface.

While there have been many suggestions in the prior art of methods ofand devices for determining the specific color ofl a sur-v .fa'ce and ofstating that specific color inl terms capable definitely to identify thecolor refered to descriptively, so that the arts and industries may beinformed by the def scription of the exact color we are aware of nosystem of the/sort o sufficient convenience, sufficient accuracy, andsuiiicient freedom from the requirement for skllled operation of theestimator of the c olor to reach the large iield of vutility waiting forsome such system. Painters, whether industrial lor artistic, decorators,dyers, dress.

makers,l potters, enamelers, electro-platers, printers of wall paper,textile fabrlcs .and colored illustrative or display books, pictures orposters; weavers and finishersv of textile fabrics; theV makers ofpigments, paints, dyes and stains, as `welll as many others practisingthe industrial arts are dependent upon guess-work or ocular es timationof the color of materials or of surfaces, in the absence of any accuratesystem of nomenclature, mensuration of the chromatic appearances, orother system of standards relating to color adapted to serve as thebasis of'communication from one artisan to another', and upon which thecolor of a surface can be accurately described. This is a considerablehandicap in each of these arts.

We are aware that physicists have been able to analytically determinethe quantitative components of a colored surface by the use of suchinstruments as the colorimeter,

by the quantitative prismatic analysis of the to whom aworkable colorstandard wouldv bev of the most practical assistance. We are also awareof various more or less scientific schemes for the production of acomparison standard by the use of a large number of indexed and arrangedcolored leaves o r a classified system of comparison car which theybelong, and identified'by a suitablersymbol expressing the=place of theparticular card in the respective scales of Value or absolute refiectingpower; of hue or wave-length (which may also contain primary, secondaryand tertiary compound .wave-lengths) and ofchroma or saturation (i. e.purity of color). r

It is obvious that the utility and practical benefit of a system ofstandards of the kind referred to will depend4 upon its capacity torespond to demands made upon it by the relatively unskilled, first, toenable ready finding ofatest or index card which matches in hue, inchroma, and in value the color of the surface, piece of cloth orwhatever is to be expressed in terms of the standard; and second, uponthe certainty with which the color so found can be' related to others,and to a communicable notation referring to the particular value, chromaand hue of the matching index.

Objects of this invention are to provide a practicable standard of theindividual and separable card character above referred to 1n which itwill be as easy as possible to find any desired color in the standard;and in which it will be vpossible to tell in what direct1on, if any, anyparticular color varies from any selected specimen of the standard; andthird, which shall provide a notation for the different index orcomparison cards of the greatest simplicity and which will fix theposition of the selected color in the standard, and which will informthose familiar with the system of a particular hue, chroma, and value ofthe color referred to by the notation onlv.

BosTo-N, MASSACHUSETTS, AND ADELBERT Amas, Jn., or HANOVER, NEWHAMPSHIRE.

ar- `ranged to be detached from the group to We shall describe theinvention in conneci scale steps in chroma and in value appro.

priate to one particular hue or wave-length to which that sheet or leafis devoted, and characterized by an appropriate systematic arrangementand construction enabling an individual card which isthe standard foraparticular combination vof value and chroma of the hue or wave-length tobe rmoved from and returned to the chart or leaf.

In the accompanying drawings:

Fig.1 is a face view of va sheet corresponding toone hue, and containingcards for each combination of chroma and value of that hue;

Fig. 2 is a section on the line 2-2 of Fig. 1;v

Fig. 3 is a section on the line 3-3 of Fig. l; y

Fig. 4 is enlarged detail of the chromatic surface of one of the cards;and

Fig. 5 is a similar detail of the reverse surface of one of the cards.

Referring to Fig. 1, the system as a whole may comprise any desiredsufficient number ofsheets 1 to represent each necessary step in thescale of one of the three qualities of hue, chroma or value upon whichthe notation, mensuration and identification of color is based; bypreference, a sufficient number of sheets to represent certain arbitrarypoints in the scale of wave-lengths of light; certain arbitrarysecondary colors identified by two wave-lengths in different parts ofthe spectrum; and, if desired, by certain tertiary colors identified by4mixtures or simultaneous emissions ofl three different wave-lengths inthe spectrum. But one such sheet is shown on he drawings, since it istypical of anyl of the number chosen, but it will be understood that theentire standard comprises as many sheets like the sheet 1 as may benecessary',each sheet being devoted to the variations in chroma and invalue, according to the selected scale, of a particular hue orwave-length.

In the instance shown the combinations, and therefore the number ofseparate comparison cards are built u by arbitrarily assuming fifteenstages oiJ value and ten stages of chroma or purity of color. Theorderly arrangement of these on the sheet representing the hue is ofgreat importance; we prefer and recommend the arrangements shown inwhich the cards are arranged on the rectangular sheet in verticalparallel columns and also in horizontal parallel rows, the variationsupward from row to row representing increasing illumination or value;and the variations from column to column from right to left representingdecreasing purity or chroma.

According to such a standard the Card bearing the color ofthe utmostpurity and deepest value will be the last card to the right and towardthe bottom of the sheet. If the horizontal rows are numbered from thebottom upward as shown from 1 to 15, and if the vertical rows are`indicated by symbols alphabetically, or, as shown by the Roman numeralsI to X, then we may refer to any card on the sheet, to indicate itsposition both on the sheet andin the respective scales of value andchroma, by giving the two coordinate numbers. For instance, the cardindicated at a in Fig. 1 is 13 X which means that this card is of themaximum purity of color (chroma X) and is two steps in value from themaximum (15). Bearing in mind that the maximum saturation obtainable inany pigment is far short of the theoretical saturation of the emittedlight of the desired wave-length, the card 2 may well represent themaximum attainable purity -of the selected hue; Let us suppose that thesheet 1 is the sheet referring to yellow of the wave-length of thesodium or D lines in the spectrum. The whole sheet shown in Fig. 1 thenrefers to variations based on yellow light of the wavev length .5887,and the card-2 at a bears a coating of a suitable pigment reflectingthis color.- As shown in Fig. 4.-, a preferred form of the standardindices 2 is a rectangular card, which preferably is provided with anopening b, so that the surface may be laid over or viewed by sightingagainst that colo-r which is to be matched'.

If the card at 13 X designated by a is colored with'the most saturatedpigment of the desired wave-length, cards in the rows 14' land 15respectively have surfaces pigmented with the pure color lightened bythe cable base, such as paper or sheet Celluloid, ofv

which the cards 2, Figs. 4 and 5 may be made. From Aright to left of theseries of cards shown in Fig. l, the purity of color of the pigmentedsurfaces falls off by a similar series of evaluated steps representing aproportional admixture with a pure pigmentof a neutral graycorresponding in value to appropriate steps for the horizontal row` 1nwhich the card is to be found. .The card at 1-1 is black; the card at 21 is Aone step lighter and neutral, but in color contains the first orminimum admixturebf the color of the column X; the card at 2`II is thesame in value as the card at 2 1, but contains the second degree in stepof admixture of the color. While impossible to indicate in the drawingthese gradations, theyhave been diagrammed arbitrarily by lindicatingthe chroma by vertical shading, and indicating the value by horizontalshading. p

We regard the construction of the sheets and cards indicated asimportant to the utility of the system as a whole. The individual cards2, beside having the opening b, are shouldered at 3 and provided with anintegral tongue 4, which may be perforatedv the cloth backing 23, 24 isfirmly glued. The laminated sheets 21, 23,22, 24 are fastened togetherby rows of sewed lock stitches as indicated at 26 (see Fig. 3) theserows being evenly spaced and extending vertically. Between every otherpair of rows the front laminated sheet 2l, 23 is slotted at 27, Figs. 1and 2, to form openings adapted to red ceive the integral projectionsforv the individual cards 2.

The whole system in the gradations recommended contains aboutthirty-three hundred cards according to the arbitrary selection of stepsin the wave-length of the spectrum and of the arbitrary choosing ofsecondary colors. Tertiary colors are so nearly represented by themodified chroma of primary and secondary colors that their inclusion isnot recommended. We find that a satisfactory arrangement of steps forthe hues or colors comprises 27 primary'and secondary hues. Thesecondary colors included among these are found in the purples(admixtures of wave-lengths in the blue and in the red end of thespectrum) and in the browns (admixtures of wave-lengths in the green andin the red portions ofthe spectrum). The symbols on the backs of thecards 2 as shown in Fig. S'may be arbitrarily chosen, for instance,yellow, -as shown, being represented by Y, ora-nge being represented byO, a yellow of a greater wave-length by O-Y (orange-yellow) and a yellowof a lesser wave-length by Y-O (yellow-orange) and so on. Preferably, ineach instance the group of symbols identifying a hue, and a. class ofcards includes the wave-length, as .5887 for the yellow shown. If thiswere a mixture color such as a purple the symbol would contain bothwave-lengths, as .4900- .6600 for example, compounded of the blue at theF line and the red at the C line of Franhofers scale of the spectrum.-But any other consistent designation of the component wave-lengths ornotation of the elements of the color may be lsubstituted within ourinvention.

lVhat we claim 1s:

l. A system of color standards comprising distinct and separable coloredstandard indices arranged in classes, each class corresponding to onehue, the indices rin said class representing orders of stepsrespectively of The sheets 21, 22 are of paper or indurated libre towhich to represent a purple` separable standard index on each Sheet foreach combination of a predetermined number of steps in chroma within thehue with a predeterminedil number of steps in value within ,the hue.

3. A system of color standards arranged to group together thecombinations of particular intensities, by steps, of chroma and of valueof a particular hue, comprising a sheet supporting a class of separablestandard indices arranged in columns according to the steps in chroma,and arranged within the columns in accordance with the steps in value.

4. A system of color standards providing a plurality of sheetscorresponding in number to all of the distinct different hues withrespect to which comparison is to be effected, each sheet being adaptedand arranged to hold removably in visible position an orderly series ofstandard indices, each standard index in a column on the sheet beingcolored to correspond to one step in a scale of intensity of chroma orpurity of the hue corresponding to the sheet, and each series in acolumn of standard indices corresponding to a particular step in chromabeing colored according to a different value from the next in saidseries.

5. A sheet element for a system of color standards comprising a luralityof sheets lUU joined together at interva s, one of the sheets beingslotted between the junctures to provide seats for a portion ofremovable standard indices, in combination with index elelments havingtongues adapted to be inserted in and held by friction in said slots,and having a portion colored according to the chroma and valueappropriate to the position of the index element on a sheet.

6. A standard index for a system of color standards having acoloredsurfac, and a projection adapted to engage a slotted sheet.

7. In a system of color standards a sheet supporting a series of indicesof the same hue arranged in a predetermined order in accordance withvariations in chroma in one dimension and value in another dimension,each index having a body portion spaced from the supporting sheet and asight opening in the said body portion.

8. In a system of color standards a sheet 9. The combination of a sheethavin y a classification symbol thereon and havlng seats arranged incoordinate series respectively designated according to columns andlines, with a series of color standard indices bearing symbolsdesignating the class, the line and the column in the holder to whichthe standard index belongs.

10. A system of color standards comprising a series of holders and aseries of distinct and severally separable colored standard comparisonelements arranged in classes, each class corresponding to one hue, thestandard comparison elements in said classes representing orders ofsteps respectively of value and chroma, there being one standardcomparison element for each combination of a particular step in valuewith each particular step in chroma.

11. A system of color standards arranged to group together the combinatins of particular intensities by steps of chroma and of value of aparticular hue, comprising a supporting sheet which carries a class ofseparable, colored, standard comparison elements arranged in columnsaccording to steps in chroma, and arranged within the columns inaccordance with steps in value, each comparison element bearing symbolsidentifying its classilication according to both chroma and value. lSigned at Boston, Massachusetts, this sixth day of July, 1922.

BLANCHE AMES AMES.

Si ed at Hanover, New Hampshire, this 8th ay of July, 1922.

l ADELBERT AMES, JR.

